The invention relates, in general, to the passive measurement of the trajectory of a ballistic projectile and, in particular, to the determination of the miss distance of a projectile fired from a tank main gun under tactical conditions.
Armor warfare emphasizes the tactical application of a tank's intrinsic maneuverability and firepower to close with, engage, and destroy enemy forces. The primary weapon system employed is the tank main gun which fires highly accurate, high velocity kinetic energy projectiles. Enemy forces are normally other armored vehicles, often in defilade. These opponents present relatively small targets, hence successful engagements demand a high degree of accuracy from both the main gun system and its ammunition. While both the main gun system and its ammunition are inherently accurate, variations in conditions between engagements (e.g. propellant temperature or thermal conditions of the gun system), not accounted for in the ballistic solution used by the fire control system, can lead to first round misses. When this occurs, the gunner has only a short time to correct aim and fire again before rounds are launched by the opposing forces. Estimation of the aim error is complicated by the natural tension of battle and the short timelines associated with tank engagements. A tactical advantage could conceivably be gained if the correction process, or at least the determination of the aim error, were automated in a fashion that would not degrade the normal firing tempo. An automatic miss distance indicator can assist in this correction process.